President Trump and Robert F. Kennedy Jr. have vowed to tackle what they describe as a scourge threatening American children. The rise in autism has been precipitous: One in 36 children is affected today, up from four in 10,000 in the 1980s, the president warned in a recent executive order. Under Mr. Kennedy’s direction, the Centers for Disease Control and Prevention plans to investigate whether vaccines are the cause — despite overwhelming evidence that they are not.

But what if there’s no mystery to be solved? What if autism is not becoming more common at all? What if the rise in diagnoses is a good thing?

As a scientist with autism, I believe the rise in diagnoses is the result of greater awareness, better identification (especially among women and girls) and a broader definition that now includes a range of neurodevelopmental conditions under the umbrella of autism spectrum disorder.

As a child, I often stared into space, missed social cues and delivered long monologues about my specific interests. But it was not until I was 53 that I suspected I had autism spectrum disorder.

The idea arose during a professional review for which my employer had brought in a psychologist. After interviewing my co-workers and me, the psychologist suggested that I might have autism, which subsequent evaluations confirmed.

It’s hard to grasp how a seventyfold increase in autism cases could mostly reflect changes in diagnosis or heightened awareness, but my experience helps make sense of it. When I was growing up in the late 1960s, autism was mostly diagnosed among children who had huge difficulties in daily functioning and needed extensive support. I wasn’t flagged for evaluation or diagnosis, but that might be different today.